TWI529425B - An optical filter and an image pickup device including the filter - Google Patents

Description

Optical filter and imaging device containing the same

The present invention relates to an optical filter and an image pickup apparatus including the same.

In the past, optical filters have been used to prevent visual sensitivity correction or resolution of a camera, a digital camera, a mobile phone with a camera function, and the like.

For example, a camera, a digital camera, a mobile phone with a camera function, and the like use a CCD or CMOS image sensor of a solid-state image sensor of a color-image, but these solid-state image sensors have sensitivity to near-infrared rays in the light-receiving portion. Since the photodiode is necessary for visual sensitivity correction, most of the near-infrared color filters are used.

Further, in a light amount adjusting device such as a lens device used in a lens optical system such as a camera, a digital camera, or a camera with a camera function, or a shutter device that also functions as a diaphragm device, in order to prevent hunting or diffraction The resolution of the image is reduced, and an optical filter such as an ND filter is used.

As a raw material of the substrate of the optical filters, PET (polyethylene terephthalate) or PEN (polyethylene naphthalate) and a norbornene-based resin material are known (Patent Document 1). However, the glass transition temperature of the resin materials is as low as 70 to 180 ° C and there is insufficient heat resistance.

Further, Patent Document 2 describes an infrared absorption filter comprising a polycarbonate resin having an anthracene skeleton and a dye having infrared absorption energy.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] JP-A-2005-338395

[Patent Document 2] JP-A-2006-119383

An object of the present invention is to provide an optical filter excellent in light transmittance, heat resistance, heat resistant coloring property, and mechanical strength.

As a result of the active review of the above problems, the present inventors have found that the above-mentioned problem can be solved by using an optical filter having a substrate and a dielectric multilayer film containing an aromatic polyether polymer having a specific glass transition temperature. Further, the heat-resistant coloring property is excellent, and thus the present invention has been completed.

That is, the present invention provides the following [1] to [9].

[1] An optical filter comprising an optical filter having a substrate and a dielectric multilayer film formed on at least one side of the substrate, the substrate comprising a differential scanning calorimetry (DSC, temperature rise) The obtained glass transition temperature (Tg) at a rate of 20 ° C /min) is an aromatic polyether polymer of 230 to 350 ° C.

[2] The optical filter according to [1], wherein the aromatic polyether polymer has a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2) At least one structural unit (i) selected by the group,

【化1】

(In the formula (1), R ¹ to R ⁴ each independently represent a one-valent organic group having 1 to 12 carbon atoms, and a to d each independently represent an integer of 0 to 4),

[Chemical 2]

(In the formula ^{(2), R 1 ~ R} 4 each independently and a ~ d of the formula (R 1) in the ¹ ~ R ⁴ and a ~ d synonymous, Y represents a single bond, -SO ₂ - or> C = O, R ⁷ and R ⁸ each independently represent a halogen atom, a carbon number of 1 to 12, an organic group or a nitro group, and g and h each independently represent an integer of 0 to 4, and m represents 0 or 1, but m is 0. When R ^{7 is} not a cyano group).

[3] The optical filter according to the above [1], wherein the aromatic polyether polymer further has a structural unit represented by the following formula (3) and is represented by the following formula (4). At least one structural unit selected from the group consisting of structural units (ii),

[化3]

(In the formula (3), R ⁵ and R ⁶ each independently represent a one-valent organic group having 1 to 12 carbon atoms, and Z represents a single bond, -O-, -S-, -SO ₂ -, >C=O, - CONH-, -COO- or a divalent organic group having a carbon number of 1 to 12, and e and f each independently represent an integer of 0 to 4, and n represents 0 or 1),

【化4】

(Formula ^{(4), R 7, R 8, Y} , m, g and h are each independently of the formula (R 2) in the ^{7, R 8, Y, m} , g and h are synonymous, R ^5, R ⁶ , Z, n, e, and f are each independently synonymous with R ⁵ , R ⁶ , Z, n, e, and f in the above formula (3).

[4] The optical filter according to [3], wherein the aromatic polyether polymer has a molar ratio of the structural unit (i) to the structural unit (ii) of 50:50 to 100: 0.

[5] The optical filter according to any one of [1] to [4] wherein the aromatic polyether polymer is converted into polystyrene by a gel permeation chromatography (GPC). The weight average molecular weight is 5,000 to 500,000.

[6] The optical filter according to any one of [1] to [5] wherein the substrate has a total light transmittance of 85% or more as measured by a JIS K7105 transparency test method at a thickness of 30 μm.

[7] The optical filter according to any one of [1], wherein the substrate has a YI value (yellowing index) of a thickness of 30 μm of 3.0 or less.

[8] The optical filter according to any one of [1], wherein the substrate has a phase difference (Rth) of 200 nm or less in a thickness direction of a thickness of 30 μm.

[9] An image pickup device comprising the optical filter according to any one of [1] to [8].

The optical filter of the present invention has excellent light transmittance, heat resistance, heat resistance coloring property, and mechanical strength, and has a small phase difference in the thickness direction. Therefore, the filter of the present invention can be applied to an image pickup apparatus.

<Optical Filter>

The optical filter of the present invention comprises a substrate and a dielectric multilayer film formed on at least one side of the substrate, wherein the substrate comprises a differential scanning calorimetry (DSC, temperature increase rate of 20 ° C / min). An aromatic polyether polymer having a glass transition temperature (Tg) of 230 to 350 °C.

The optical filter of the present invention is excellent in light transmittance, heat resistance, heat resistance coloring property, and mechanical strength, and has a small phase difference in the thickness direction. Therefore, the optical filter of the present invention can be suitably used for an image pickup apparatus.

Further, in the case where the optical filter of the present invention absorbs strong light, damage due to an increase in temperature of the filter due to absorption of light or deterioration of optical characteristics is also less.

In the present invention, the term "heat-resistant coloring property" means that the coloring resistance is excellent when exposed to a high temperature, and it is difficult to color, for example, when heat-treated in the air at a high temperature (230 ° C) for about 1 hour.

<Substrate> [Aromatic Polyether Polymer]

The glass transition temperature of the aromatic polyether polymer is preferably from 240 to 330 ° C, more preferably from 250 to 300 ° C.

The base material containing such an aromatic polyether polymer is excellent in light transmittance, heat resistance, heat resistance coloring property, and mechanical strength, and is therefore suitable for use in an optical filter. Further, since heating or heat treatment can be performed at the time of forming a dielectric multilayer film on at least one surface of the substrate at a high temperature, an optical filter excellent in optical characteristics can be obtained.

The aromatic polyether polymer is a polymer obtained by a reaction of forming an ether bond in a main chain, and preferably has a structural unit represented by the following formula (1) (hereinafter also referred to as "structural unit (1)) And a polymer of at least one structural unit (i) selected from the group consisting of structural units (hereinafter also referred to as "structural unit (2)") represented by the following formula (2). By having the polymer having the structural unit (i), an aromatic polyether having a glass transition temperature of 230 to 350 ° C can be obtained. The substrate containing the polymer maintains colorless transparency at the time of manufacture of the optical filter and in a long-term use environment.

【化5】

In the above formula (1), R ¹ to R ⁴ each independently represent a one-valent organic group having 1 to 12 carbon atoms, and a to d each independently represent an integer of 0 to 4, preferably 0 or 1, more preferably 0.

The one-valent organic group having 1 to 12 carbon atoms may be a one-valent hydrocarbon group having 1 to 12 carbon atoms, and a carbon number of 1 to 12 having at least one atom selected from the group consisting of oxygen atoms and nitrogen atoms. Wait.

The one-valent hydrocarbon group having 1 to 12 carbon atoms is exemplified by a linear or branched hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, and an aromatic hydrocarbon group having 6 to 12 carbon atoms.

The hydrocarbon group of the linear or branched chain having 1 to 12 carbon atoms is preferably a linear or branched hydrocarbon group having 1 to 8 carbon atoms, more preferably a linear or branched hydrocarbon group having 1 to 5 carbon atoms.

Preferred specific examples of the straight or branched hydrocarbon group are methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, t-butyl, n-pentyl, n-hexyl and Positive heptyl and so on.

The alicyclic hydrocarbon group having 3 to 12 carbon atoms is preferably an alicyclic hydrocarbon group having 3 to 8 carbon atoms, more preferably an alicyclic hydrocarbon group having 3 or 4 carbon atoms.

Preferred specific examples of the alicyclic hydrocarbon group having 3 to 12 carbon atoms are exemplified by cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl; cyclobutenyl, cyclopentenyl and cyclohexenyl; A cycloalkenyl group. The bonding site of the alicyclic hydrocarbon group may be any carbon on the alicyclic ring.

The aromatic hydrocarbon group having 6 to 12 carbon atoms is exemplified by a phenyl group, a biphenyl group, a naphthyl group and the like. The bonding site of the aromatic hydrocarbon group may be any carbon on the aromatic ring.

The organic group having 1 to 12 carbon atoms containing an oxygen atom is exemplified by an organic group formed by a hydrogen atom, a carbon atom and an oxygen atom, and a total of an ether bond, a carbonyl group, an ester bond and a hydrocarbon group is preferred. An organic group having a carbon number of 1 to 12, and the like.

The organic group having a carbon number of 1 to 12 having an ether bond may, for example, be an alkoxy group having 1 to 12 carbon atoms, an alkenyloxy group having 2 to 12 carbon atoms, an alkoxy group having 2 to 12 carbon atoms, or a carbon number of 6 to 12 An aryloxy group and an alkoxyalkyl group having 2 to 12 carbon atoms. Specific examples thereof include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a phenoxy group, a propyleneoxy group, a cyclohexyloxy group, and a methoxymethyl group.

Further, the organic group having a total carbon number of 1 to 12 of a carbonyl group may be exemplified by a fluorenyl group having 2 to 12 carbon atoms. Specifically, it is exemplified by an ethyl group, a propyl group, an isopropyl group, and a benzamidine group.

The organic group having a total carbon number of 1 to 12 having an ester bond is exemplified by a decyloxy group having 2 to 12 carbon atoms. Specifically, it is exemplified by an ethoxycarbonyl group, a propenyloxy group, a isopropyloxy group, a benzamidine group or the like.

The organic group having 1 to 12 carbon atoms of the nitrogen atom is exemplified by an organic group formed by a hydrogen atom, a carbon atom and a nitrogen atom, and specifically exemplified by a cyano group, an imidazolyl group, a triazolyl group, a benzimidazolyl group and a benzene group. And triazolyl and the like.

The organic group having 1 to 12 carbon atoms containing an oxygen atom and a nitrogen atom is exemplified by an organic group formed by a hydrogen atom, a carbon atom, an oxygen atom and a nitrogen atom, and specifically exemplified by an oxazolyl group, an oxadiazolyl group, and a benzene group. And oxazolyl and benzooxadiazolyl and the like.

R ¹ to R ⁴ in the above formula (1) are preferably a hydrocarbon having 1 to 12 carbon atoms, more preferably an aromatic hydrocarbon group having 6 to 12 carbon atoms, more preferably a phenyl group.

【化6】

The formula (2), R ¹ ~ R ⁴ each independently and a ~ d of the formula (1), the R ¹ ~ R ⁴ and a ~ d synonymous, Y represents a single bond, -SO ₂ - or> C = O, R ⁷ and R ⁸ each independently represent a halogen atom, a carbon number of 1 to 12, an organic group or a nitro group, and m represents 0 or 1. However, when m is 0, R ^{7 is} not a cyano group. g and h each independently represent an integer of 0 to 4, preferably 0.

The one-valent organic group having 1 to 12 carbon atoms is exemplified by the same organic group as the one-valent organic group having 1 to 12 carbon atoms in the above formula (1).

The molar ratio of the aforementioned structural unit (1) to the structural unit (2) of the polymer (however, the total of the two (structural unit (1) + structural unit (2)) is 100), optical properties, heat resistance From the viewpoint of mechanical properties, the preferred structural unit (1): structural unit (2) = 50: 50 ~ 100: 0, better structural unit (1): structural unit (2) = 70: 30 ~ 100: 0, and better construction unit (1): construction unit (2) = 80:20~100:0.

Here, the mechanical property means a property such as tensile strength, elongation at break, and tensile modulus of the polymer.

Further, the polymer may further have at least one structural unit (ii) selected from the group consisting of the structural unit represented by the following formula (3) and the structural unit represented by the following formula (4). When the polymer has the structural unit (ii), the mechanical properties of the substrate containing the polymer can be improved, which is preferable.

【化7】

In the above formula (3), R ⁵ and R ⁶ each independently represent a one-valent organic group having 1 to 12 carbon atoms, and Z represents a single bond, -O-, -S-, -SO ₂ -, >C=O, - CONH-, -COO- or a divalent organic group having 1 to 12 carbon atoms, n represents 0 or 1, and e and f each independently represent an integer of 0 to 4, preferably 0.

The one-valent organic group having 1 to 12 carbon atoms is exemplified by the same organic group as the one-valent organic group having 1 to 12 carbon atoms in the above formula (1).

The divalent organic group having 1 to 12 carbon atoms may be a divalent hydrocarbon group having 1 to 12 carbon atoms, a divalent halogenated hydrocarbon group having 1 to 12 carbon atoms, or at least one atom selected from the group consisting of an oxygen atom and a nitrogen atom. The divalent organic group having 1 to 12 carbon atoms and the divalent halogenated organic group having 1 to 12 carbon atoms and at least one atom selected from the group consisting of an oxygen atom and a nitrogen atom.

The divalent hydrocarbon group having 1 to 12 carbon atoms is exemplified by a linear or branched divalent hydrocarbon group having 1 to 12 carbon atoms, a divalent alicyclic hydrocarbon group having 3 to 12 carbon atoms, and a divalent aromatic hydrocarbon having 6 to 12 carbon atoms. Hydrocarbyl group and the like.

The divalent hydrocarbon group of a straight or branched chain having 1 to 12 carbon atoms is exemplified by a methylene group, an ethylidene group, a trimethylene group, an isopropylidene group, a pentamethylene group, a hexamethylene group, and a heptamethylene group.

The divalent alicyclic hydrocarbon group having 3 to 12 carbon atoms is exemplified by a cycloalkyl group such as a cyclopropyl group, a cyclobutene butyl group, a cyclopentylene group and a cyclohexylene group; a cyclobutenyl group and a cyclopentenyl group; A cycloalkenyl group such as a cyclohexene group. The bonding site of the alicyclic hydrocarbon group may be any carbon on the alicyclic ring.

The divalent aromatic hydrocarbon group having 6 to 12 carbon atoms is exemplified by a stretching phenyl group, a stretching naphthyl group, and a stretching phenyl group. The bonding site of the aromatic hydrocarbon group may be any carbon on the aromatic ring.

The divalent halogenated hydrocarbon group having 1 to 12 carbon atoms is exemplified by a divalent halogenated hydrocarbon group having a linear or branched chain of 1 to 12 carbon atoms, a divalent halogenated aliphatic hydrocarbon group having 3 to 12 carbon atoms, and a carbon number of 6 to 12 A halogenated aromatic hydrocarbon group or the like.

The divalent halogenated hydrocarbon group of a straight or branched chain having 1 to 12 carbon atoms is exemplified by difluoromethylene, dichloromethylene, tetrafluoroextension ethyl, tetrachloroexetylethyl, hexafluorotrimethyl, and hexa. Chlorotriazine methyl, hexafluoroisopropylidene and hexachloroisopropylidene.

The divalent halogenated alicyclic hydrocarbon group having 3 to 12 carbon atoms is exemplified by a hydrogen atom, a chlorine atom, a bromine atom or an iodine atom of at least a part of the groups exemplified in the above-mentioned divalent alicyclic hydrocarbon group having 3 to 12 carbon atoms. Replace the base and so on.

The divalent halogenated aromatic hydrocarbon group having 6 to 12 carbon atoms is exemplified by a hydrogen atom of at least a part of the groups exemplified in the above-mentioned divalent aromatic hydrocarbon group having 6 to 12 carbon atoms, which is substituted by a fluorine atom, a chlorine atom, a bromine atom or an iodine atom. Cheng Zhiji and so on.

The organic group having 1 to 12 carbon atoms of at least one atom selected from the group consisting of an oxygen atom and a nitrogen atom is exemplified by an organic group formed by a hydrogen atom and a carbon atom, and an oxygen atom and/or a nitrogen atom, and is exemplified. It is a divalent organic group having an ether bond, a carbonyl group, an ester bond or a guanamine bond, and a hydrocarbon group having 1 to 12 carbon atoms.

The divalent halogenated hydrocarbon group having 1 to 12 carbon atoms and containing at least one atom selected from the group consisting of an oxygen atom and a nitrogen atom is specifically exemplified as a carbon containing at least one atom selected from the group consisting of an oxygen atom and a nitrogen atom. A group in which at least a part of hydrogen atoms of the exemplified group in the divalent organic group of 1 to 12 are substituted with a fluorine atom, a chlorine atom, a bromine atom or an iodine atom.

Z in the above formula (3) is preferably a single bond, -O-, -SO ₂ -, >C=O or a divalent organic group having 1 to 12 carbon atoms, more preferably a divalent carbon number of 1 to 12. a hydrocarbon group or a divalent halogenated hydrocarbon group having 1 to 12 carbon atoms; and the divalent hydrocarbon group having 1 to 12 carbon atoms is preferably a divalent hydrocarbon group having a linear or branched chain of 1 to 12 carbon atoms or a divalent hydrocarbon having a carbon number of 3 to 12 An alicyclic hydrocarbon group.

【化8】

Formula ^{(4), R 7, R 8, Y} , m, g , and h (2) in the R each independently in the above formula ^{7, R 8, Y, m} , g and h are synonymous, R ^5, R ^6, Z, n, e, and f are each independently synonymous with R ⁵ , R ⁶ , Z, n, e, and f in the above formula (3). Further, when m is 0, R ^{7 is} not a cyano group.

The molar ratio of the aforementioned structural unit (i) to the aforementioned structural unit (ii) (but the total of the two ((i) + (ii)) is 100), in terms of optical properties, heat resistance and mechanical properties From the viewpoint, it is preferably (i): (ii) = 50: 50 to 100: 0, more preferably (i): (ii) = 70: 30 to 100: 0, and more preferably (i) :(ii)=80:20~100:0.

From the viewpoints of optical properties, heat resistance and mechanical properties, the polymer preferably contains 70 mol% or more of all structural units including the structural unit (i) and the structural unit (ii), and more preferably all structural units. 95% of the total is more than 95%.

[Synthesis method of polymer]

The polymer may be, for example, a compound represented by the following formula (5) (hereinafter also referred to as "compound (5)") and a compound represented by the following formula (7) (hereinafter also referred to as "compound (7)" The component (A) of at least one compound selected from the group consisting of reacting with the component (B) containing a compound represented by the following formula (6).

【化9】

In the above formula (5), X independently represents a halogen atom, and is preferably a fluorine atom.

【化10】

In the formula ^{(7), R 7, R} 8, Y, m, g and h are each independently of the formula R (2) in the ^{7, R 8, Y, m} , g and h are synonymous, X is independently of the formula (5) X is synonymous. However, when m is 0, R ^{7 is} not a cyano group.

【 化11 】

In the above formula (6), R ^a each independently represents a hydrogen atom, a methyl group, an ethyl group, an ethyl sulfonyl group, a methanesulfonyl group or a trifluoromethylsulfonyl group, and among them, a hydrogen atom is preferred. Further, in the formula (6), R ¹ to R ⁴ and a to d are synonymous with R ¹ to R ⁴ and a to d in the above formula (1), respectively.

Specific examples of the above compound (5) include 2,6-difluorobenzonitrile, 2,5-difluorobenzonitrile, 2,4-difluorobenzonitrile, 2,6-dichlorobenzonitrile, and 2, Reactive derivative of 5-dichlorobenzonitrile, 2,4-dichlorobenzonitrile and the like. In particular, 2,6-difluorobenzonitrile and 2,6-dichlorobenzonitrile are suitable from the viewpoint of reactivity and economy. These compounds may also be used in combination of two or more.

The compound represented by the above formula (6) (hereinafter also referred to as "compound (6)") is specifically exemplified as 9,9-bis(4-hydroxyphenyl)fluorene, 9,9-bis(3-phenyl). 4-hydroxyphenyl)anthracene, 9,9-bis(3,5-diphenyl-4-hydroxyphenyl)anthracene, 9,9-bis(4-hydroxy-3-methylphenyl)anthracene, 9,9-bis(4-hydroxy-3,5-dimethylphenyl)anthracene, 9,9-bis(4-hydroxy-3-cyclohexylphenyl)anthracene, and the like, and the like. Among the above compounds, 9,9-bis(4-hydroxyphenyl)anthracene and 9,9-bis(3-phenyl-4-hydroxyphenyl)anthracene are suitable. These compounds may also be used in combination of two or more.

Specific examples of the above compound (7) include 4,4'-difluorobenzophenone, 4,4'-difluorodiphenylanthracene, 2,4'-difluorobenzophenone, and 2, 4'-Difluorodiphenyl fluorene, 2,2'-difluorobenzophenone, 2,2'-difluorodiphenyl fluorene, 3,3'-dinitro-4,4'-difluoro Benzophenone, 3,3'-dinitro-4,4'-difluorodiphenyl fluorene, 4,4'-dichlorobenzophenone, 4,4'-dichlorodiphenyl fluorene, 2,4'-dichlorobenzophenone, 2,4'-dichlorodiphenyl fluorene, 2,2'-dichlorobenzophenone, 2,2'-dichlorodiphenyl fluorene, 3, 3'-Dinitro-4,4'-dichlorobenzophenone and 3,3'-dinitro-4,4'-dichlorodiphenylphosphonium. Among these, 4,4'-difluorobenzophenone and 4,4'-difluorodiphenylfluorene are preferred. These compounds may also be used in combination of two or more.

The at least one compound selected from the group consisting of the compound (5) and the compound (7) preferably contains 80 mol% to 100 mol%, more preferably 90 mol%, in 100 mol% of the component (A). 100% by mole.

Further, the component (B) preferably contains a compound represented by the following formula (8) as needed.

The compound (6) preferably contains 50 mol% to 100 mol%, more preferably 80 mol% to 100 mol%, and more preferably 90 mol% in 100 mol% of the component (B). 100% by mole.

【化12】

In the aforementioned formula (8) R ^5, in the R ^6, Z, n, e and f are each independently of the formula ^{(3) R 5, R 6} , Z, n, e and f are synonymous, R ^a in the above formula (6) R ^{a is} synonymous.

The compound represented by the above formula (8) is exemplified by hydroquinone, metaxyl phenol, 2-phenylhydroquinone, 4,4'-biphenol, 3,3'-biphenol, 4,4'-di. Hydroxydiphenyl hydrazine, 3,3'-dihydroxydiphenyl hydrazine, 4,4'-dihydroxybenzophenone, 3,3'-dihydroxybenzophenone, 2,2-bis(4- Hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane And other reactive derivatives and the like. These compounds may also be used in combination of two or more.

Among the above compounds, resorcin, 4,4'-biphenol, 2,2-bis(4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane, 4,4'-biphenol is preferred from the viewpoint of reactivity and mechanical properties . These compounds may also be used in combination of two or more.

More specifically, the above polymer can be synthesized by the method (I') shown below.

Process (I'): After reacting the component (B) with an alkali metal compound in an organic solvent to obtain an alkali metal salt of the component (B), the obtained alkali metal salt is allowed to react with the component (A). Further, the alkali metal salt of the component (B) can be reacted with the component (A) by reacting the component (B) with an alkali metal compound in the presence of the component (A).

The alkali metal compound used in the reaction may, for example, be an alkali metal such as lithium, potassium or sodium; a hydrogenated alkali metal such as lithium hydride, potassium hydride or sodium hydride; or an alkali metal hydroxide such as lithium hydroxide, potassium hydroxide or sodium hydroxide; An alkali metal carbonate such as lithium carbonate, potassium carbonate or sodium carbonate; an alkali metal hydrogencarbonate such as lithium hydrogencarbonate, potassium hydrogencarbonate or sodium hydrogencarbonate. These may be used alone or in combination of two or more.

The alkali metal compound is usually 1 to 3 equivalents, preferably 1.1 to 2 equivalents, more preferably 1.2 to 1.5 times the amount of the metal atoms in the alkali metal compound, relative to all -OR ^a in the above component (B). The amount of equivalent is used.

The organic solvent used in the reaction may be N,N-dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone or 1,3-dimethyl-2-imidazole. Linone, γ-butyrolactone, cyclobutyl, dimethyl hydrazine, diethyl hydrazine, dimethyl hydrazine, diethyl hydrazine, diisopropyl hydrazine, diphenyl hydrazine, diphenyl ether , benzophenone, dialkoxybenzene (carbon number 1 to 4 of alkoxy group), and trialkoxybenzene (alkoxy group number 1-4). Among these solvents, it is preferred to use a high dielectric constant such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, cyclobutyl, diphenylanthracene or dimethylarylene. Organic solvents. These may be used alone or in combination of two or more.

Further, in the above reaction, a solvent azeotropic with water such as benzene, toluene, xylene, hexane, cyclohexane, octane, chlorobenzene, dioxane, tetrahydrofuran, anisole or phenylethyl alcohol may be further used. These may be used alone or in combination of two or more.

When the ratio of the component (A) to the component (B) is 100 mol% based on the total of the component (A) and the component (B), the component (A) is preferably 45 mol% or more and 55 mol% or less. It is preferably 50 mol% or more and 52 mol% or less, more preferably more than 50 mol% and 52 mol% or less, and the component (B) is preferably 45 mol% or more and 55 mol% or less, more preferably 48% by mole or more and 50% by mole or less, more preferably 48% by mole or more and less than 50% by mole.

Further, the reaction temperature is preferably from 60 ° C to 250 ° C, more preferably from 80 ° C to 200 ° C. The reaction time is preferably from 15 minutes to 100 hours, more preferably from 1 hour to 24 hours.

[Physical properties of polymers, etc.]

The polymer is measured by a HLC-8220 type GPC apparatus (column: TSKgelα-M, development solvent: tetrahydrofuran (hereinafter also referred to as "THF") manufactured by TOSOH, and the weight average molecular weight (Mw) in terms of polystyrene is preferably 5,000 to 500,000, more preferably 15,000 to 400,000, and even more preferably 30,000 to 300,000.

The thermal decomposition temperature of the polymer measured by thermogravimetric analysis (TGA) is preferably 450 ° C or higher, more preferably 475 ° C or higher, and still more preferably 490 ° C or higher.

[Method of Manufacturing Substrate]

The method for producing the substrate is not particularly limited, but a polymer composition containing the polymer is applied onto a support to form a coating film, and then an organic solvent is removed from the coating film to form a substrate on the support. The method.

By forming the substrate by such a method, it is possible to prevent the molecules of the polymer from being aligned in a certain direction, so that a substrate having a smaller phase difference can be obtained.

As the polymer composition described above, a mixture of the polymer obtained by the above method (I') and an organic solvent can be used as it is. By using the polymer composition, the substrate can be easily and inexpensively produced.

Further, the polymer composition may be obtained by separating (purifying) the polymer into a solid component from a mixture of the polymer obtained in the above method (I') and an organic solvent, and then dissolving in an organic solvent to prepare a polymer composition.

The method of separating (purifying) the aforementioned polymer into a solid component can be carried out, for example, by reprecipitating the polymer in a weak solvent of a polymer such as methanol, followed by filtration, followed by drying under reduced pressure or the like.

The organic solvent in which the polymer is dissolved is preferably used, for example, dichloromethane, tetrahydrofuran, cyclohexanone, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and Γ-butyrolactone is preferably dichloromethane, N,N-dimethylacetamide or N-methylpyrrolidone from the viewpoint of coatability and economy. These solvents may be used alone or in combination of two or more.

The concentration of the polymer in the polymer composition in which the polymer is dissolved depends on the molecular weight of the polymer, but is usually from 5 to 40% by mass, preferably from 7 to 25% by mass. When the polymer concentration in the polymer composition is within the above range, the film thickness can be increased, pinholes are less likely to occur, and a substrate having excellent surface smoothness can be formed.

The viscosity of the polymer composition is determined by the molecular weight or concentration of the polymer, but is usually 2,000 to 100,000 mPa ‧ , preferably 3,000 to 50,000 mPa ‧ s. When the viscosity of the polymer composition is within the above range, the composition in the film formation is excellent in the retention property, and the thickness is easily adjusted, so that the formation of the substrate is easy.

Further, the polymer composition may contain an anti-aging agent, and by containing an anti-aging agent, the durability of the obtained substrate can be further improved.

As the anti-aging agent, a hindered phenol-based compound is preferred.

The hindered phenol-based compound which can be used in the present invention is exemplified by triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6- Hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,4-bis-(n-octylthio)-6-(4-hydroxyl -3,5-di-t-butylanilino)-3,5-triazine, pentaerythritol bismuth [3-(3,5-t-butyl-4-hydroxyphenyl)propionate], 1, 1,3-Shen[2-methyl-4-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propenyloxy]-5-t-butylphenyl] Alkane, 2,2-thio-di-extended ethyl bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3, 5-di-t-butyl-4-hydroxyphenyl)propionate, N,N-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrocinnamate), 1,3,5-trimethyl-2,4,6-glucosin (3,5-di-t-butyl-4-hydroxybenzyl)benzene, cis-(3,5-di-t-butyl -4-hydroxybenzyl)-isocyanurate, and 3,9-bis[2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propanoxime] -1,1-Dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane and the like.

When the anti-aging agent is formulated in the above polymer composition, the amount of the anti-aging agent is preferably from 0.01 to 10 parts by weight based on 100 parts by weight of the polymer.

The method of applying the polymer composition onto a support to form a coating film is exemplified by a roll coating method, a gravure coating method, a spin coating method, a method using a squeegee, and the like.

The thickness of the coating film is not particularly limited and is, for example, 1 to 250 μm, preferably 2 to 150 μm, more preferably 5 to 125 μm.

The support is exemplified by a polyethylene terephthalate (PET) film, a SUS plate, and the like.

The method for removing the above organic solvent from the coating film is not particularly limited, and is exemplified by a method of heating the coating film.

The heating conditions are as long as the organic solvent can be removed from the coating film, and may be appropriately determined depending on the support or the polymer. For example, the heating temperature is preferably from 30 ° C to 300 ° C, more preferably from 40 ° C to 250 ° C, and even more preferably 50. °C~230°C. The heating time is preferably from 10 minutes to 5 hours.

Further, the heating may be carried out in two or more stages. Specifically, it is dried at a temperature of 30 to 80 ° C for 10 minutes to 2 hours, and then heated at 100 ° C to 250 ° C for 10 minutes to 2 hours. Alternatively, it may be dried under a nitrogen atmosphere or under reduced pressure as needed.

Further, when the substrate is produced, after the organic solvent is removed from the coating film, the coating film from which the solvent is removed is preferably fired. When a substrate is produced, a substrate having a small heat shrinkage rate can be obtained by including a baking step. Therefore, the dielectric multilayer film can be easily formed on the substrate.

In the calcination, the coating film formed on the support may be fired together with the support. However, from the viewpoint of not affecting the properties of the support, the coating film formed on the support is preferably peeled off from the support. Subsequent firing. Further, the method of removing the organic solvent from the coating film may be carried out by firing the coating film, but also including the step of removing the organic solvent before the firing step. Further, when the coating film is peeled off from the support and the coating film is fired, it is preferred to include a step of removing the organic solvent from the coating film before peeling off the coating film from the support.

The calcination step is preferably carried out at a specific temperature, and the firing temperature is preferably from 210 ° C to 350 ° C, more preferably from 220 ° C to 330 ° C, and even more preferably from 230 ° C to 320 ° C. The firing time is preferably from 10 minutes to 5 hours.

The firing atmosphere is not particularly limited, and is preferably an atmosphere or an inert gas atmosphere, and is preferably an inert gas atmosphere.

The inert gas is exemplified by nitrogen, argon, helium or the like from the viewpoint of coloring property, and preferably nitrogen.

The obtained substrate may be used by peeling from the support, or may be used as it is without peeling depending on the use of the support or the type or the composite used.

The thickness of the substrate is appropriately selected depending on the intended use, but is preferably from 1 to 250 μm, more preferably from 2 to 150 μm, still more preferably from 10 to 125 μm.

When the phase difference of the substrate and the weight of the display device are considered, the film thickness of the substrate is preferably thin.

[Physical properties of the substrate, etc.]

The glass transition temperature (Tg) of the substrate measured by a Model 8230 DSC measuring apparatus (temperature rising rate: 20 ° C /min) manufactured by Rigaku Co., Ltd. is preferably 230 to 350 ° C, more preferably 240 to 330 ° C, and even more preferably 250. ~300 °C.

When the substrate has the glass transition temperature, heating or heat treatment can be performed when a dielectric multilayer film is formed on at least one surface of the substrate at a high temperature, so that an optical filter having particularly excellent optical characteristics can be easily produced.

When the thickness of the substrate is 30 μm, the total light transmittance in the JIS K7105 transparency test method is preferably 85% or more, more preferably 88% or more. The total light transmittance can be measured using a turbidimeter SC-3H (manufactured by Suga Test Machine Co., Ltd.).

When the thickness of the substrate is 30 μm, the light transmittance at a wavelength of 400 nm is preferably 70% or more, more preferably 75% or more, still more preferably 80% or more. The light transmittance at a wavelength of 400 nm can be measured by an ultraviolet ‧ visible light spectrophotometer V-570 (manufactured by JASCO Corporation).

By setting the transmittance of the substrate to this range, the substrate can exhibit a particularly high light transmittance, so that the substrate can be preferably used for an optical filter.

When the thickness of the substrate is 30 μm, the YI value (yellowness index) is preferably 3.0 or less, more preferably 2.5 or less, still more preferably 2.0 or less. The YI value can be measured using an SM-T type color measuring device manufactured by Suga Test Machine Co., Ltd. By setting the YI value within this range, a substrate which is not easily colored can be obtained, and it can be applied to an optical filter.

Moreover, when the thickness of the base material is 30 μm, the YI value (YI value after heating) after heating in a hot air dryer at 230 ° C for 1 hour in the air is preferably 3.0 or less, more preferably 2.5 or less. Better to be 2.0 or less. By setting the YI value within this range, a substrate which is not easily colored even at a high temperature can be obtained, and an optical filter excellent in optical characteristics can be obtained.

The substrate preferably has a refractive index of 1.60 to 1.75, more preferably 1.60 to 1.70, for light having a wavelength of 633 nm. The refractive index can be measured by a prism coupler model 2010 (manufactured by Metricon Co., Ltd.).

The tensile strength of the substrate is preferably from 50 to 200 MPa, more preferably from 80 to 150 MPa. The tensile strength can be measured by a tensile tester 5543 (manufactured by INSTRON Co., Ltd.).

The elongation at break of the substrate is preferably from 5 to 100%, more preferably from 15 to 100%. The elongation at break can be measured by a tensile tester 5543 (manufactured by INSTRON Co., Ltd.).

The tensile modulus of the substrate is preferably from 2.5 to 4.0 GPa, more preferably from 2.7 to 3.7 GPa. The tensile modulus of elasticity can be measured by a tensile tester 5543 (manufactured by INSTRON Co., Ltd.).

When the thickness of the substrate is 30 μm, the phase difference (Rth) in the thickness direction is preferably 200 nm or less, more preferably 50 nm or less, still more preferably 10 nm or less. The phase difference can be measured using a RETS spectrometer manufactured by Otsuka Electronics Co., Ltd.

When the substrate has such a low phase difference, the substrate is excellent in optical isotropic properties. When an optical filter containing the substrate is used in an image pickup apparatus, coloring or interference fringes on the display surface can be prevented, and the performance of the image pickup apparatus can be prevented from being lowered. Therefore, the optical filter of the present invention can be preferably used in an image pickup apparatus.

The substrate has a linear expansion coefficient of preferably 80 ppm/K or less, more preferably 75 ppm/K or less, as measured by an SSC-5200 type TMA measuring apparatus manufactured by Seiko Instruments.

The humidity expansion coefficient of the substrate is preferably 15 ppm/% RH or less, more preferably 12 ppm/% RH or less. The humidity expansion coefficient can be measured using a TMA (SII Nano Technology, TMA-SS6100) humidity control equipment. When the expansion coefficient of the substrate is within the above range, the substrate exhibits high dimensional stability (environmental reliability), and thus it can be more suitably used as an optical filter.

[Substrate containing near-infrared absorbing agent]

When the optical filter of the present invention is used as a near-infrared cut filter, it is preferred that the substrate include, for example, a near-infrared ray absorbing agent. The substrate containing the near-infrared ray absorbing agent can be produced by the same method as the method for producing the substrate, for example, by using a composition obtained by blending a near-infrared absorbing agent in the polymer composition.

The near-infrared absorbing agent may, for example, be a compound having a maximum absorption (λ _max ) at a wavelength of 600 to 800 nm.

Examples of such near-infrared ray absorbing agents include cyanine dyes, phthalocyanine dyes, aminium dyes, iminium dyes, azo dyes, anthraquinone dyes, and diimine quinone pigments. , squaraine dyes and porphyrin pigments.

The base material containing the near-infrared ray absorbing agent having the maximum absorption in the specific wavelength region is small in dependence on the angle of incident light, and can stably determine the near-infrared ray absorption wavelength on the short-wavelength (visible light) side, so that only the latter will be used. Compared with the past near-infrared cut filter in which the near-infrared reflection wavelength of the short-wavelength (visible light) side changes with the incident angle, the dielectric multilayer film can be changed with respect to the incident angle and the change of the transmission characteristic. A smaller near-infrared cut filter.

Specific examples of the commercial product of the near-infrared ray absorbing agent include Lumogen IR765 and Lumogen IR788 (manufactured by BASF Corporation); ABS643, ABS654, ABS667, ABS670T, ABS694, IRA693N, and IRA735 (manufactured by Exciton); SDA3598, SDA6075, and SDA8030 , SDA8303, SDA8470, SDA3039, SDA3040, SDA3922, SDA7257 (manufactured by HWSANDS); TAP-15, IR-706 (manufactured by Yamada Chemical Industry Co., Ltd.).

These near-infrared ray absorbing agents may be used alone or in combination of two or more.

In the present invention, the amount of the near-infrared ray absorbing agent used is appropriately selected depending on the desired characteristics, but is usually 0.01 to 10.0% by weight, preferably 0.01 to 8.0, based on 100% by weight of the polymer contained in the substrate. The weight % is more preferably 0.01 to 5.0% by weight.

When the amount of use of the near-infrared ray absorbing agent is within the above range, the incident angle dependence of the absorption wavelength is small, and a near-infrared cutoff filter having a near-infrared cutoff energy and a transmittance and strength in the range of 450 to 600 nm can be obtained.

When the amount of the near-infrared absorbing agent used is more than the above range, although a near-infrared cut filter having a characteristic of a near-infrared absorbing agent can be obtained, the transmittance in the range of 450 to 600 nm is low. After the desired value or the strength of the substrate and the near-infrared cut filter is lowered, when the amount of the near-infrared absorbing agent used is less than the above range, the transmittance in the range of 450 to 600 nm can be obtained. In the case of the infrared cut filter, the characteristics of the near-infrared absorbing agent are not easily expressed, and it is difficult to obtain a near-infrared cut filter having a small incident angle dependence of the absorption wavelength.

Preferred values of glass transition temperature, YI value, YI value after heating, tensile strength, elongation at break, tensile modulus, coefficient of linear expansion, and coefficient of humidity expansion of a substrate containing a near-infrared absorbing agent are described in The glass transition temperature, the YI value, the YI value after heating, the tensile strength, the elongation at break, the tensile modulus, the coefficient of linear expansion, and the coefficient of humidity expansion are preferably the same in the column of the physical properties of the substrate. .

Further, the substrate containing the near-infrared ray absorbing agent may be colored by the near-infrared ray absorbing agent used. Accordingly, the YI value of the substrate containing the near-infrared absorbing agent may also become a negative value. Since the optical member such as the optical filter preferably does not have a yellow taste, even if the YI value of the substrate containing the near-infrared ray absorbing agent becomes a negative value, a substrate for an optical filter can be used.

[Substrate containing pigments and/or dyes]

When the optical filter of the present invention is used as the ND filter, it is preferred that the substrate contains, for example, a pigment and/or a dye. The base material containing the pigments and/or dyes can be produced by the same method as the method for producing the base material, except for the composition obtained by mixing the pigments and/or dyes in the polymer composition.

The pigment is not particularly limited, but is a pigment having an absorption pigment in a visible light region, and preferably having a uniform absorption in a visible light region (a flat spectral transmittance curve is displayed in a visible light region), preferably At least one inorganic particle selected from the group consisting of metal, carbon black, metal oxide, metal nitride, and metal oxynitride. The aforementioned inorganic particles are more preferably inorganic ultrafine particles.

The amount of the pigment used is preferably from 0.01 to 5% by weight, more preferably from 0.05 to 3% by weight, based on 100% by weight of the polymer used in the substrate.

When the pigment is contained in the above-mentioned base material in an amount as described above, moderate light absorption is observed in the visible light region, and an ND filter having a desired optical density can be easily produced.

The metal, metal oxide, metal nitride and metal oxynitride having absorption in the visible light region may be metal monomers, oxides, nitrides, and oxynitrides of any metal, but preferably belong to the elemental period. Metallic monomers, oxides, nitrides, and oxynitrides of metals of Groups 3 to 11 of the fourth cycle of the Table. Among the 3rd to 11th groups of the fourth cycle of the periodic table, it is strontium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), Nickel (Ni) and copper (Cu), among which Ti, Mn, Fe or Cu is preferred.

Further, the metal oxide is preferably a composite oxide composed of two or more kinds of metals, and is preferably a metal composite oxide composed of copper, iron and manganese. The composition ratio of the metal composite oxide composed of copper, iron, and manganese is not particularly limited. However, when the metal composite oxide composed of copper, iron, and manganese is 100% by weight, it is preferred to have copper oxide. 5 to 30% by weight, iron oxide is 25 to 70% by weight, and manganese oxide is a metal composite oxide having a composition ratio of 25 to 70% by weight.

The spectral transmittance curve in the visible light region of the metal composite oxide composed of the oxides of copper, iron, and manganese is flat, so the ND filter of the metal composite oxide is used in visible light. A flat spectral transmittance curve is shown in the region, and is preferred.

The primary particle diameter of the inorganic particles is preferably from 5 to 100 nm, more preferably from 20 to 70 nm. The effect of suppressing the scattered light of the ND filter is obtained by causing the primary particle diameter to fall within the range. According to this, it is possible to prevent the resolution of the ND filter from being lowered, ghosting of the screen, and glare.

In the present invention, the form of the pigment in the base material may be a form in which the primary particles are directly dispersed, or the primary particles to be added may be agglomerated to form a second or three or more aggregated particles, or may be mixed once. A form in which particles and secondary particles are agglomerated and dispersed. In either case, the average particle diameter of the particles in the substrate is preferably from about 50 to 600 nm, more preferably from about 50 to 400 nm, still more preferably from about 50 to 200 nm. When a pigment having the average particle diameter is used, the turbidity value of the ND filter can be lowered, which is preferable.

Further, the dye is not particularly limited as long as it is a dye having absorption in the visible light region.

When a dye composed of an organic substance is used, absorption with a specific wavelength is caused by its chemical structure. Therefore, in the present invention, when the substrate contains only a specific pigment and the spectral transmittance curve of the ND filter is not flat, by using a wavelength region in the vicinity of the maximum value of the spectral transmittance curve The specific dye having absorption is blended with the pigment in the aforementioned substrate to flatten the spectral transmittance curve of the ND filter.

Accordingly, the dye having absorption in the visible light region is exemplified by phthalocyanine, thiol metal complex, azo, polymethine, diphenylmethane, triphenylmethane, lanthanum, lanthanum. A pigment compound such as a lanthanide or a diammonium lanthanide.

Commercially available dyes having absorption in the visible light region in the present invention are listed as SDA4137, SDA4428, SDA9800, SDA9811, SDB3535 (above, manufactured by SANDS), KAYASORB series, Kayaset series (above, manufactured by Nippon Kayaku Co., Ltd.) .

Preferred values and records of glass transition temperature, YI value, YI value after heating, tensile strength, elongation at break, tensile modulus, coefficient of linear expansion and coefficient of humidity expansion of a substrate containing a pigment and/or a dye The glass transition temperature, the YI value, the YI value after heating, the tensile strength, the elongation at break, the tensile modulus, the coefficient of linear expansion, and the coefficient of humidity expansion of the substrate in the column of the physical properties of the substrate, etc. The preferred values are the same.

<Dielectric Multilayer Film>

The above dielectric multilayer film can be produced by a conventional method.

Specifically, the dielectric multilayer film may be a multilayer film in which a high refractive index material layer and a low refractive index material layer are laminated.

As the material constituting the high refractive index material layer, a material having a refractive index of 1.7 or more can be used, and a material having a refractive index range of usually 1.7 to 2.5 is selected.

These materials are exemplified by, for example, titanium oxide, zirconium oxide, antimony pentoxide, antimony pentoxide, antimony oxide, antimony oxide, zinc oxide, zinc sulfide or indium oxide as a main component, and contain a small amount of titanium oxide, tin oxide and/or oxidation. Hey, etc.

The material constituting the low refractive index material layer may be a material having a refractive index of 1.6 or less, and a material having a refractive index generally selected from 1.2 to 1.6.

Such materials are exemplified by, for example, cerium oxide, aluminum oxide, cerium fluoride, magnesium fluoride, sodium aluminum hexafluoride or the like.

The method of forming the dielectric multilayer film on at least one side of the substrate is not particularly limited, and the cross-laminated high refractive index material layer and the low refractive index can be formed by, for example, a CVD method, a sputtering method, a vacuum evaporation method, or the like. a dielectric multilayer film formed by a material layer, which is bonded to the substrate by an adhesive, and laminated on the substrate by direct, CVD, sputtering, vacuum evaporation, or the like. Obtained from a layer of high refractive index material and a layer of low refractive index material.

Among these, from the viewpoint of the uniformity of the obtained dielectric multilayer film or the adhesion of the multilayer film to the substrate, it is preferred to form a film directly on the substrate by sputtering.

The temperature at which the high refractive index material layer and the low refractive index material layer are formed by sputtering is determined depending on the material to be used, but is preferably 150 to 350 ° C, more preferably 180 to 300 ° C, and more preferably 220 °. 260 ° C.

When the dielectric multilayer film is formed on the substrate, it is preferably carried out at such a high temperature. By forming a dielectric multilayer film at a high temperature, an optical filter which is less prone to cracking can be obtained even when exposed to a high temperature.

The step of forming a dielectric multilayer film on a substrate is usually carried out at a high temperature of 200 ° C or higher. Accordingly, in order to withstand such a high temperature, in particular, since the Tg minus 20 to 30 ° C causes a change in the elastic modulus due to the dynamic viscoelasticity measurement of the substrate (manufactured by BAIBURON Co., Ltd.), the substrate is used. The polymer contained is required to have a Tg (measured by DSC) higher than the heating temperature by 20 ° C or higher. The substrate forming the aforementioned member requires heat resistance of at least 230 ° C or higher, and is preferably heat resistance of 230 to 350 ° C, more preferably 240 to 330 ° C, and more preferably 250 to 300 ° C. Therefore, it is preferred that the glass transition temperature of the polymer contained in the substrate also falls within the range.

Since the polymer has a Tg within the above range, a material which is a substrate for forming a dielectric multilayer film can be preferably used.

Since the base material is excellent in heat resistance, even when a dielectric multilayer film is directly formed on a substrate, the temperature range in which the film can be formed is wide. Therefore, the dielectric multilayer film can be easily formed on the aforementioned substrate without deteriorating the performance of the dielectric multilayer film.

The thickness of each of the high refractive index material layer and the low refractive index material layer is usually a thickness of 0.1 λ to 0.5 λ of the infrared wavelength λ (nm) to be interrupted. When the thickness falls within the above range, the product of the refractive index (n) and the film thickness (d) (n × d) becomes the same value as the optical film thickness calculated by the formula λ/4, and the optical characteristic relationship of the reflection ‧ refraction is maintained Therefore, there is a tendency to easily control the interception and transmission of a specific wavelength.

Further, the number of layers of each of the high refractive index material layer and the low refractive index material layer is preferably from 5 to 50 layers, more preferably from 10 to 45 layers.

Further, when the dielectric multilayer film is vapor-deposited on the substrate, the dielectric multilayer film can be deposited on both sides of the substrate by the elimination of the dielectric film, and the vapor deposition dielectric on the substrate can be performed. A method of irradiating a surface of the multilayer film with radiation such as ultraviolet rays. Further, when the radiation is irradiated, it may be irradiated while forming the dielectric multilayer film, or may be additionally irradiated after the formation of the dielectric multilayer film.

<Optical Filter>

The optical filter of the present invention is excellent in optical characteristics, heat-resistant coloring property, and the like. Therefore, it is possible to use a near-infrared cut filter which is used for visual sensitivity correction of a solid-state imaging device which is mainly used for a camera module, such as a CCD or a CMOS, or an ND (dimming) which is mainly used for light amount adjustment for preventing resolution reduction. Filter.

The optical filter of the present invention can be used in particular for digital cameras, cameras for mobile phones, digital video recorders, PC cameras, surveillance cameras, automotive cameras, mobile information terminals, personal computers, video game consoles, medical devices, USB memories. Body, portable game console, fingerprint identification system, digital music player, toy robot, toys, etc. Further, a hot wire cut filter or the like which is mounted on a glass such as an automobile or a building can be used.

Since the optical filter of the present invention has heat resistance corresponding to a specific operation step, it is possible to completely mount the camera module completely for the main substrate, and based on the foregoing characteristics, especially as an optical filter for a camera module, Quality ‧ Cost ‧ The design side can expect substantial benefits.

The optical filter may be heated when it is used (assembled) in a medium such as an image pickup apparatus. It is preferable to have heat resistance which can correspond to the solder reflow step. Therefore, the optical filter preferably does not cause cracking or the like on the dielectric multilayer film formed on the substrate after being exposed to a high temperature (for example, after heating at 250 ° C for 10 minutes). The change of the multilayer film.

Since the optical filter of the present invention has a substrate excellent in heat resistance and heat-resistant coloring property, the temperature at which the dielectric multilayer film is formed on the substrate can be high. Therefore, even if the optical filter of the present invention is exposed to a high temperature, it is less likely to cause cracking and is a filter excellent in thermal stability.

Further, the optical filter of the present invention may be provided with an antireflection layer as needed. The antireflection layer is not particularly limited as long as it can prevent or reduce the interface between the substrate and the air, and/or the visible light at the interface between the boundary layer of the boundary layer and the air. The antireflection layer is preferably formed on the surface of the substrate opposite to the surface on which the dielectric multilayer film is laminated.

The antireflection layer can be laminated by laminating the first to fourth layers of the high refractive index material and the low refractive index material described in the dielectric multilayer film by, for example, a CVD method, a sputtering method, a vacuum deposition method, or the like. form.

Further, the method of forming the antireflection layer is exemplified by a method of forming an antireflection layer by an imprint method on the surface of the substrate, or by using a titanium alkoxide compound and an alkoxysilane compound as a raw material, respectively. A method of forming an antireflection layer by wet coating as a high refractive index material and a low refractive index material.

Further, the lyogel material is usually thermally hardened, but an anti-reflection layer can be formed by using energy rays (for example, ultraviolet rays) to generate an acid or the like which is a condensation catalyst and harden it to form an anti-reflection layer (JP-2000-109560). , special open 2000-1648).

In the above, as for the material and equipment used for forming the dielectric multilayer film, a method of forming an antireflection layer in the same manner as the formation of the above dielectric multilayer film can be used, or productivity can be improved. From the viewpoint of the above, a method of forming an antireflection layer by the above wet coating is preferably used.

<Camera device>

The image pickup apparatus of the present invention comprises the aforementioned optical filter of the present invention.

The optical filter of the present invention is excellent in optical characteristics, excellent in heat resistance, heat-resistant coloring property, and mechanical strength, and is excellent in weight, and is excellent in thermal shock resistance. Therefore, an image pickup device having excellent performance, light weight, and thinness can be obtained.

The imaging device of the present invention is exemplified by a digital camera, a camera for a mobile phone, a digital video recorder, a PC camera, a surveillance camera, and a camera for an automobile.

[Examples]

Hereinafter, the present invention will be specifically described by way of examples.

(1) Structural analysis

The structural analysis of the polymer obtained in the following examples and comparative examples was carried out by IR (ATR method, FT-IR, 6700, manufactured by NICOLET) and NMR (ADVANCE 500 type, manufactured by BRUKAR Co., Ltd.).

(2) Weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw/Mn)

The weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw/Mn) of the polymers obtained in the following examples and comparative examples were HLC-8220 type GPC apparatus manufactured by TOSOH (column: TSKgelα). -M, developing solvent: THF).

(3) Glass transition temperature (Tg)

The glass transition temperature of the polymer and the evaluation film obtained in the following examples and comparative examples was measured at a temperature increase rate of 20 ° C/min using a Model 8230 DSC measuring apparatus manufactured by Rigaku Corporation.

(3') thermal decomposition temperature

The thermal decomposition temperatures of the polymers obtained in the following examples and comparative examples were measured by thermogravimetric analysis (TGA: nitrogen gas atmosphere, temperature increase rate 10 ° C / min, 5% weight reduction temperature).

(4) Mechanical strength

The tensile strength, elongation at break and tensile modulus at room temperature of the film for evaluation obtained in the following examples and comparative examples were measured by a tensile tester 5543 (manufactured by INSTRON Co., Ltd.) in accordance with JIS K7127.

(5) Environmental safety

The coefficient of linear expansion of the film for evaluation obtained in the following examples and comparative examples was measured using an SSC-5200 type TMA measuring apparatus manufactured by Seiko Instruments. After heating from room temperature to 280 ° C, the linear expansion coefficient was calculated from the gradient at 200 ° C to 100 ° C when the temperature was lowered at 3 ° C / min.

The humidity expansion coefficient of the film for evaluation obtained in the following examples and comparative examples was measured under the following conditions using a humidity control apparatus of TMA (manufactured by SII Nano Technology Co., Ltd., TMA-SS6100).

Humidity conditions: change the humidity from 40% RH to 70% RH per 10% RH (stretching method: load 5g), temperature: 23 °C

(6) Optical properties

The total light transmittance and the YI value of the film for evaluation obtained in the following examples and comparative examples were measured in accordance with JIS K7105 transparency test method. Specifically, the total light transmittance of the film for evaluation was measured using a turbidimeter SC-3H (manufactured by Suga Test Instruments Co., Ltd.), and the YI value was measured using an SM-T type color measuring instrument manufactured by Suga Test Instruments Co., Ltd. (before heating) YI).

In addition, the evaluation film obtained in the following Examples and Comparative Examples was measured by a hot air dryer using an SM-T color measuring instrument manufactured by Suga Test Instruments Co., Ltd., and the YI value after heating at 230 ° C for 1 hour in the air. (YI after heating).

The light transmittance of the film for evaluation obtained in the following examples and comparative examples at a wavelength of 400 nm was measured using an ultraviolet ‧ visible light spectrophotometer V-570 (manufactured by JASCO Co., Ltd.), and the refractive index of the film for evaluation was used. Mirror coupler model 2010 (manufactured by Metricon).

Further, the phase difference (Rth) of the film for evaluation obtained in the following examples and comparative examples was measured using a RETS spectroscope manufactured by Otsuka Electronics Co., Ltd. Further, the reference wavelength at the time of measurement was 589 nm, and the evaluation film thickness of the phase difference was expressed by a value of 30 μm.

(7) Evaluation of optical film

The film for evaluation obtained in the following examples was cut into a square of 10 cm × 10 cm, and a multilayer vapor-deposited film capable of reflecting near-infrared rays was formed on one surface of the obtained film at an evaporation temperature of 150 ° C. [Interlayered cerium oxide (SiO) ₂ : a film thickness of 120 to 190 nm) and a layer of titanium dioxide (TiO ₂ : film thickness: 70 to 120 nm), the number of laminations is 50]. Next, an optical filter was produced by laminating ultraviolet rays of 1 J/cm ² in a nitrogen atmosphere using a metal halide lamp to which a cold mirror was attached to the surface of the multilayer deposited film on the substrate. The spectral transmittance curve of the optical filter was measured using a spectrophotometer (manufactured by Hitachi, Ltd., U-3140).

When the transmittance of the obtained optical filter in the near-infrared region of the wavelength of 750 to 1000 nm is 5% or less, it is referred to as "○".

The evaluation results of the optical filter are shown in Table 1.

(8) Evaluation of crack resistance of optical film

The film for evaluation obtained in the following examples and comparative examples was cut into a square of 10 cm × 10 cm, and a multilayer vapor-deposited film capable of reflecting near-infrared rays was formed on both sides of the obtained film at an evaporation temperature of 200 ° C [interactive lamination oxidation An optical filter was produced by forming a layer of yttrium (SiO ₂ : film thickness: 120 to 190 nm) and a layer of titanium oxide (TiO ₂ : film thickness: 70 to 120 nm) and laminating 50 layers. The obtained optical filter was heated in an oven at 250 ° C for 10 minutes to visually evaluate whether or not the vapor deposited film was cracked before and after heating. The case where no crack was found was recorded as "○".

The evaluation results of the optical filter are shown in Table 1.

[Example 1]

(A) component was added to a 3 L four-necked flask: 2,6-difluorobenzonitrile (hereinafter also referred to as "DFBN") 35.12 g (0.253 mol), and (B) component: 9,9-bis (4- Hydroxyphenyl) hydrazine (hereinafter also referred to as "BPFL") 70.08 g (0.200 mol), resorcin (hereinafter also referred to as "RES") 5.51 g (0.050 mol), potassium carbonate 41.46 g (0.300 mol), N,N-dimethylacetamide (hereinafter also referred to as "DMAc") 443 g and toluene 111 g. Next, a four-necked flask was equipped with a thermometer, a stirrer, a three-way valve with a nitrogen introduction tube, a Dean-Stark tube, and a cooling tube.

Next, after replacing the inside of the flask with nitrogen, the resulting solution was reacted at 140 ° C for 3 hours, and the resulting water was removed from the Dean-Stark tube at any time. After the formation of water was not confirmed, the temperature was slowly raised to 160 ° C, and the reaction was carried out at this temperature for 6 hours.

After cooling to room temperature (25 ° C), the resulting salt was removed with a filter paper, and the filtrate was poured into methanol to reprecipitate, and the filtrate (residue) was separated by filtration. The obtained filtrate was vacuum dried overnight at 60 ° C to obtain a white powder (polymer) (yield: 95.67 g, yield 95%).

The physical properties of the obtained polymer are shown in Table 1. The structural analysis of the obtained polymer and the weight average molecular weight were carried out. As a result, the infrared absorption spectrum of the characteristic absorption of 3035cm ^-1 (CH ^{stretching), 2229cm -1 (CN),} 1574cm -1, 1499cm ( aromatic ring skeleton ^{absorption) -1, 1240cm -1 (-O-)} , weight average molecular weight It is 130,000.

Next, the obtained polymer was redissolved in DMAc to obtain a polymer composition having a polymer concentration of 20% by mass. The polymer composition was applied onto a substrate made of polyethylene terephthalate (PET) using a doctor blade, dried at 70 ° C for 30 minutes, and then dried at 100 ° C for 30 minutes to form a film, and then from a PET substrate. Stripped. Subsequently, the film was fixed on a mold frame, and further fired at 230 ° C for 2 hours to obtain a film for evaluation having a film thickness of 30 μm.

The physical properties of the obtained film for evaluation are shown in Table 1.

[Embodiment 2]

The same procedure as in Example 1 was carried out except that 11.41 g (0.050 mol) of 2,2-bis(4-hydroxyphenyl)propane was used instead of RES 5.51 g. The physical properties of the obtained polymer and the film for evaluation are shown in Table 1.

[Example 3]

In addition to using BPFL 78.84g (0.225mol) and 2,2-bis(4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane 8.41g (0.025mol) instead of BPFL 70.08g and RES 5.51 g was carried out in the same manner as in Example 1 except for the component (B). The physical properties of the obtained polymer and the film for evaluation are shown in Table 1.

[Example 4]

The same procedure as in Example 1 was carried out except that 9,9-bis(3-phenyl-4-hydroxyphenyl)fluorene 125.65 g (0.250 mol) was used instead of BPFL 70.08 g and RES 5.51 g as the component (B). The physical properties of the obtained polymer and the film for evaluation are shown in Table 1.

[Example 5]

The same procedure as in Example 1 was carried out except that BPFL 87.60 g (0.250 mol) was used instead of BPFL 70.08 g and RES 5.51 g as the component (B). The physical properties of the obtained polymer and the film for evaluation are shown in Table 1.

[Embodiment 6]

In addition to using BPFL 78.84 g (0.225 mol) and 1,1-bis(4-hydroxyphenyl)cyclohexane 6.71 g (0.025 mol) instead of BPFL 70.08 g and RES 5.51 g as the component (B), the remainder and the examples 1 is also done. The physical properties of the obtained polymer and the film for evaluation are shown in Table 1.

[Embodiment 7]

The same procedure as in Example 5 was carried out except that DFBN 28.10 g (0.202 mol) and 4,4-difluorobenzophenone 11.02 g (0.051 mol) were used instead of DFBN 35.13 g as the component (A). The physical properties of the obtained polymer and the film for evaluation are shown in Table 1.

[Embodiment 8]

The same procedure as in Example 7 was carried out except that the amount of the component (A) was changed to 17.556 g (0.126 mol) of DFBN and 27.55 g (0.126 mol) of 4,4-difluorobenzophenone. The physical properties of the obtained polymer and the film for evaluation are shown in Table 1.

[Embodiment 9]

The same procedure as in Example 5 was carried out except that 63.56 g (0.250 mol) of 4,4-difluorodiphenylphosphonium (DFDS) was used instead of DFBN 35.12 g as the component (A). The physical properties of the obtained polymer and the film for evaluation are shown in Table 1.

[Embodiment 10]

When the polymer composition having a polymer concentration of 20% by mass was prepared, the obtained polymer was redissolved in DMAc, and then the near-infrared absorbing agent ABS670T (0.1 part by weight) was added to 100 parts by weight of the polymer in the obtained solution. The same procedure as in Example 5 was carried out. The physical properties of the obtained polymer and the film for evaluation are shown in Table 1.

[Example 11]

When the polymer composition having a polymer concentration of 20% by mass was prepared, the obtained polymer was redissolved in DMAc, and then the near-infrared absorbing agent ABS694 (0.1 part by weight) was added to 100 parts by weight of the polymer in the obtained solution. The same procedure as in Example 5 was carried out. The physical properties of the obtained polymer and the film for evaluation are shown in Table 1.

[Comparative Example 1]

In addition to 2,2-bis(4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane 84.06 g (0.250 mol) instead of BPFL 70.08 g and RES 5.51 g as component (B) The remainder was carried out in the same manner as in Example 1. The physical properties of the obtained polymer and the film for evaluation are shown in Table 1. Further, the evaluation of the optical film could not be performed because the film was deformed and melted when the colored portion was formed.

[Comparative Example 2]

The polyethylene naphthalate film (Neotex) manufactured by Teijin Co., Ltd. was evaluated in the same manner as in Example 1 (film thickness: 125 μm). The physical properties of the film are shown in Table 1. Further, the evaluation of the optical filter could not be performed because the film was deformed and melted when the colored portion was formed.

[Comparative Example 3]

To a 300 mL four-necked flask equipped with a thermometer, a stirrer, a nitrogen gas introduction tube, and a condenser, 9.70 g (23.6 mmol) of 2,2-bis[4-(4-aminophenoxy)phenyl]propane was added. Next, after replacing the inside of the flask with nitrogen, N-methyl-2-pyrrolidone (NMP) (60 ml) was added and stirred until homogeneous. 5.30 g (23.6 mmol) of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride was added to the obtained solution at room temperature, and the mixture was directly stirred at this temperature for 12 hours to carry out a reaction to obtain a polyglycine-containing solution. .

After adding NMP (75 ml) to the obtained polyamine-containing acid solution, pyridine (7.5 ml) and acetic anhydride (6.7 ml) were added, and the mixture was stirred at 110 ° C for 6 hours to carry out hydrazine imidization. Subsequently, after cooling to room temperature, a large amount of methanol was poured, and the filtrate was separated by filtration. The obtained filtrate was vacuum dried overnight at 60 ° C to obtain a white powder (polymer) (yield: 13.5 g, yield: 95.3%).

Next, the obtained polymer was redissolved in DMAc to obtain a 20% by mass resin solution. The resin solution was applied onto a substrate made of polyethylene terephthalate (PET) using a squeegee (100 μm gap), dried at 100 ° C for 30 minutes, and then dried at 150 ° C for 60 minutes to form a film. The PET substrate is peeled off. Subsequently, the film was further dried at 150 ° C under reduced pressure for 3 hours to obtain a film for evaluation having a film thickness of 30 μm. The evaluation was carried out in the same manner as in Example 1. The results are shown in Table 1.

From the above results, it is understood that the film (substrate) is excellent in light balance, heat resistance, heat resistance, and mechanical strength. Further, it is understood that the optical filter of the present invention has excellent near-infrared cut-off performance. Therefore, the optical filter of the present invention can be preferably used in an image pickup apparatus.

Claims (9)

A near-infrared cut filter, which is a near-infrared cut filter having a substrate and a dielectric multilayer film formed on at least one side of the substrate, the substrate comprising a differential scanning calorimeter (DSC) The glass transition temperature (Tg) of the temperature rise rate of 20 ° C /min is 230 to 350 ° C, and is selected from the group consisting of the structural unit represented by the following formula (1) and the structural unit represented by the following formula (2). At least one structural polystyrene polymer of the structural unit (i) and a compound having a maximum absorption at a wavelength of 600 to 800 nm, (In the formula (1), R ¹ to R ⁴ each independently represent a one-valent organic group having 1 to 12 carbon atoms, and a to d each independently represent an integer of 0 to 4), (In the formula ^{(2), R 1 ~ R} 4 each independently and a ~ d of the formula (R 1) in the ¹ ~ R ⁴ and a ~ d synonymous, Y represents a single bond, -SO ₂ - or> C = O, R ⁷ and R ⁸ each independently represent a one-valent organic group or a nitro group having 1 to 12 carbon atoms, and g and h each independently represent an integer of 0 to 4, m represents 0 or 1, but when m is 0, R ⁷ Not for cyano). The near-infrared cut filter according to claim 1, wherein the dielectric multilayer film is formed at a temperature of 150 to 350 °C. The near-infrared cut-off filter according to the first or second aspect of the invention, wherein the aromatic polyether polymer further has a structural unit represented by the following formula (3) and a structural unit represented by the following formula (4) At least one structural unit (ii) selected by the group, (In the formula (3), R ⁵ and R ⁶ each independently represent a one-valent organic group having 1 to 12 carbon atoms, and Z represents a single bond, -O-, -S-, -SO2-, >C=O, -CONH -, -COO- or a divalent organic group having 1 to 12 carbon atoms, and e and f each independently represent an integer of 0 to 4, and n represents 0 or 1), (Formula ^{(4), R 7, R 8, Y} , m, g and h are each independently of the formula (R 2) in the ^{7, R 8, Y, m} , g and h are synonymous, R ^5, R ⁶ , Z, n, e, and f are each independently synonymous with R ⁵ , R ⁶ , Z, n, e, and f in the above formula (3). The near-infrared cut filter according to claim 3, wherein in the aromatic polyether polymer, the molar ratio of the structural unit (i) to the structural unit (ii) is 50:50 to 100: 0. For example, the near-infrared cut filter of claim 1 or 2, The polystyrene-equivalent weight average molecular weight of the aromatic polyether polymer measured by a gel permeation chromatography (GPC) is 5,000 to 500,000. The near-infrared cut filter according to claim 1 or 2, wherein the substrate has a total light transmittance of 85% or more as measured by a JIS K7105 transparency test method at a thickness of 30 μm. The near-infrared cut filter according to claim 1 or 2, wherein the substrate has a YI value (yellowness index) of 3.0 or less in thickness of 30 μm. The near-infrared cut filter according to claim 1 or 2, wherein the substrate has a phase difference (Rth) of 200 nm or less in a thickness direction of 30 μm. An image pickup apparatus comprising the near-infrared cut filter according to any one of claims 1 to 8.